Does light have a mass?

[James R]

137,

<i>It never goes to n over n unless you consider a adequately defined process as erasing the troubling -1.</i>

You mean, like the adequately defined limiting processes seen in the calculus of limits?

<i>I would avoid your line of reasoning myself. It is unjustifiable, either in mathematics or calculus.</i>

I've justified it in my previous post. It's justified by our observations of the world. It's justified by the axioms and derived results of mathematics.

You quoted me...

The argument is a general one to do with space, time and relative motion. Therefore it is generally applicable to any device or system moving in space and time.

Then you said: <i>Unacceptable limitation on testing. ... Testing is always necessary. Atomic clocks may be affected differently from light clocks from electronic clocks to mechanical clocks.</i>

Not if relativity is correct. A test of one physical system justifies the application of the theory to the others because of what I said in the quote above.

<i>Are you saying that your FOR measurements are real and the other twin's measurements are real and that the observed measurements from each reciprocal twin's FOR are real?</i>

Yes, unless you want to go into the realism/instrumentalism philosophical argument.

<i>Some believe appearance is the reality. Some say it is merely appearances. This is not a matter of agreement.</i>

That is philosophy, not physics. They agree on the physics. All the physics needs to do is to make accurate predictions, which is what relativity does. The "meaning" of it all can be left to the philosophers.

<i>My point is that Einstein did not just happen to plug in light speed as a convenience. He made a conscious decision to use light as the speed limit of the measureable.</i>

Not exactly. The fact that light speed is a limit is a derived result, not an assumption. Einstein assumed only his two postulates.

<i>So a good clock is one that has to be affected by speed?</i>

Yes, if relativity is correct. But the mechanism of the clock is not affected. Time itself is affected, as Taylor and Wheeler point out in your quote.

<i>you state a] 2 clocks appear to run at different rates according to an observer but it is the nature of time itself. So which is it? Is it the appearance of different rates of time passage or is it actual time passage differences.</i>

Since there is no absolute reference frame, appearances are all we have to go on. We might as well call them real. So, both (a) and (b) are true. The nature of time itself varies with the observer.

<i>"Einstein says you cannot do that for light."
Please cite the source, so I can get schooled.</i>

The source was a statement by Einstein quoted by 137 in a previous post in this thread. You can easily look it up again.

<i>Well, hot damn if that don't sound like Schrodinger's cat; Open the box and you get the truth and it ruins the whole 'either-or' setup. So in transit there is an illusion, an appearance of symmetry where each one measures time dilation and length shortening of the other as a reality, when in reality only one twin's reality was slowed and shortened in an unseen reality within their own frame but viewed by the other one as an appearance which was actually a reality with the one twin who kept looking in the mirror and getting older while receiving updated photos of the other twin staying the same age. Paradox is resolved.</i>

No. In transit, each observer has his or her own reality, and the symmetry between their points of view is real. When the acceleration happens, that symmetry is broken, and <b>both</b> twins see the non-accelerating twin's time as running faster than the accelerating twin. When the accelerating twin finally slows to a stop relative to the other twin, the stay-at-home twin is agreed by both observers to be older than the one who travelled. Paradox is resolved.

 

[137]

this and that

James R,

You mean, like the adequately defined limiting processes seen in the calculus of limits?

&

I've justified it in my previous post. It's justified by our observations of the world. It's justified by the axioms and derived results of mathematics.

** Some Postulates regarding Zeno's paradox**

1. [/list=1]
   1. [/list=1]
      1. Axiom 1 n-1/n will never equal n/n; n-1/n will never equal zero.
      2. Axiom 2 The calculus can be applied to this formula to illustrate the approach to zero, and define the useful, acceptable magnitude.
         [/list=1] If we study atomic interaction, there will be a limit of distance between two atoms where inter-reactions become important. This may vary depending upon whether the observer is a physicist, a chemist or a street sweeper. Axiom 1 is true in the realm of mathematics. Axiom 2 does not invalidate or resolve Axiom 1 mathematically, it limits it. If your point is that a mathematical formula must have reasonable limits put on it in order to be useful to real world physics, then I agree. If you insist that Axiom 1 is invalid, then I would say, get out your abacus, scribin' paper or supercomputer and set it to work to find out where n-1/n becomes zero, without setting a limit on it.

         A test of one physical system justifies the application of the theory to the others

         This line of logic leads to potential disaster, unless you mean that one successful test justifies testing in other systems. Let us use the example of the experiment where the planes flew the atomic clocks and the atomic clocks went slower. Then we assume, as many do, that therefore relativity is correct in the realm of all time/clock predictions. We then accept that all clocks slow down x [formula result] amount. Now we fly your loved one who is a patient with a heart condition to a medical facility in France on a supersonic jet. This patient is in a plane with semi-conductor clocks that dispense medications on an hourly basis. If the person does not get the proper dosages per hour as defined in earth-based medical study, then their heart goes into arrythmeia and possibly stoppage. Do you trust the test in one system and assume it is correct for all? Do you assume that time/ processes/existence is truly slowed down and therefore let the electronic device dole out dosages by the internal hourly clock? Which frame's hour should be used to dole out the medication?

         That is philosophy, not physics. They agree on the physics. All the physics needs to do is to make accurate predictions, which is what relativity does. The "meaning" of it all can be left to the philosophers.

         regarding my words,

         Some believe appearance is the reality. Some say it is merely appearances. This is not a matter of agreement.

         Philosophers may investigate this, but it is not merely about philosophical meaning. Some agree on the mathematics, but not on the physics, to add yet another layer. If one twin is heading back at the other twin in a collision course, you better darn well know what your measurements mean in a physical sense. If it appears that you have two minutes to move out of the way, but you only 'really' have 30 seconds, then there is a direct consequence of appearances versus reality. Relativity's warning that we need to understand the difference is valid; the contention that appearance are reality is what is makes some relativists appear to enter the psuedo-science realm.

         The fact that light speed is a limit is a derived result, not an assumption.

         I said the speed of light was consciously used, not assumed.

         Time itself is affected, as Taylor and Wheeler point out in your quote.

         The quote stated only that within a framework that the clock mechanism is not affected. You may be extrapolating what you already know about their writings, but the quote does not enter into your statement.

         Since there is no absolute reference frame, appearances are all we have to go on. We might as well call them real. So, both (a) and (b) are true. The nature of time itself varies with the observer

         An appearance can sometimes correlate to reality and an appearance can sometimes not correlate to reality. The appearance of a twin racing at us at light speed can have a certain appearance, as we receive signals, but there is a specific 'spacetime' event that will occur when the collision takes place. We had better figure out whether the appearance correlates to the reality, or we may as well completely sever physics from the real world.
         
         The schrodinger's cat analogy can be made more valid to your tastes if you place each twin in a box and we know only one is really dead[at rest]. There is a symmetry of status. Only when one twin opens the other box dowe know who is at rest[permanently] and who was really moving. Yes it is not exact, and it deals with a third observer, but we can keep going for fun if you like.
         
         cheers,
         137
         
         P.S. We should be able to take a survey of folks who regularly fly supersonic jets. Statistically, they should live longer, according to earth FOR standards of longevity, than folks who have never left their home town. If we need more folks to fly more supersonic jets, for more trips, then lets begin the study today. Get old folk volunteers who get to travel for free, but must travel x number of miles each year or month even. Statistically, they should live longer than their earth bound counter parts. How fun if we only use 69 year old twins. One goes supersonic, the other stays home. Poor earthbound twin will meet her maker first, at least statistically.

 

[James R]

137,

<i>n-1/n will never equal n/n; n-1/n will never equal zero.</i>

To clear up possible confusion - I assume you actually mean (n-1)/n here, not n - (1/n).

I agree that (n-1)/n is not equal to zero (or one) for any finite value of n. However, in the (mathematical) limit as n goes to infinity, this expression becomes equal to 1. That's a perfectly well-defined mathematical operation.

I'm not sure where you're going with this. We started this discussion with Zeno's paradox. I showed you why it is not a true paradox. It was formulated before the idea of a mathematical limit was invented. That invention explains and resolves the apparent paradox. Extending things to the real world, the paradox seems to imply that motion is impossible. Clearly, it is not, and we can give an equivalent physical argument which explains why not.

Are you losing track of what you're arguing here, or is it me?

<i>Let us use the example of the experiment where the planes flew the atomic clocks and the atomic clocks went slower. ...Do you trust the test in one system and assume it is correct for all?</i>

Absolutely. I'd bet my life on it.

<i>Do you assume that time/ processes/existence is truly slowed down and therefore let the electronic device dole out dosages by the internal hourly clock?</i>

If the hourly clock is on the plane, I don't need to worry about any time dilation, since the clock is in the rest frame of the plane. If the clock works properly on the ground, it will work in the air too.

<i>Which frame's hour should be used to dole out the medication?</i>

The one in the plane. The patient is in the plane, so it is their hour which counts, not the hour of a ground observer. That's fairly obvious.

<i>Philosophers may investigate this, but it is not merely about philisophical meaning. Some agree on the mathematics, but not on the physics, to add yet another layer. If one twin is heading back at the other twin in a collision course, you better damn well know what your measurements mean in a physical sense. If it appears that you have two minutes to move out of the way, but you only 'really' have 30 seconds, then there is a direct consequence of appearances versus reality.</i>

You seem confused about this. Observers in different reference frames agree on which <b>events</b> occur. If there is a collision, all observers agree there is a collision. The only things they don't agree on are when and where the collision happens. If you avoid the collision in one reference frame, you'll avoid it in all frames. If things were different, all kinds of paradoxes would arise.

<i>We had better figure out whether the appearance correlates to the reality, or we may as well completely sever physics from the real world.</i>

Again, I'm not sure where you're going with this. You seem to be stretching for a distinction which I do not believe exists in a physical sense. Perhaps you could give me an example of relative motion in which you think the appearance would differ from the reality? Be careful to explain how you tell the difference between the appearance and the reality.

<i>The schrodinger's cat analogy ...[snip]</i>

I don't understand this part of your post, so I'm leaving it for now. If it's important, could you please explain it in more detail? (BTW, I know the Schrodinger Cat experiment, so no need to go over that.)

<i>We shoudl be able to take a survey of folks who regularly fly supersonic jets. Statistically, they should live longer, according to earth FOR standards of longevity, than folks who have never left their home town.</i>

I suggest you investigate the amount by which they live longer. Over a lifetime of flying supersonic jets, I estimate it amounts to less than a second of total extra lifespan. How are we going to investigate that? Not by survey, I don't think.

 

[137]

fine point

James R,
It may be a tangent, but it is not losing track. Yes, I mean (n-1)/n. My point is that mathematical formulas can exist or be formulated which do not correspond to reality. (n-1)/n [in the Zeno paradox] as it stands remains a mathematical paradox. The adding limits is an adjunct constraint in order to 'stop the madness' so to speak. If you change the parameters of a paradox, then you are not dealing with the original paradox. You showed how to side-step a paradox by giving it a specific 'sandbox' to play in. My point once again, and it is valid, is that a mathematical formula may not correspond to reality. If it does not correspond to reality, then the formula needs to be tested for its application to reality [if this is the point of the formula.] These thoughts are directly related to the need to test 'elegant formulas' for validity in physics. ****---removed comment about dropping this line of argument, due to rethinking of application of the paradox and claims of 'solved' plus early thread comments....see edits in>>>>**edit in 6/17/02** I do see a paradox parallel in old posts on this thread regarding the ever increasing energy added in particle acceleration. The argument goes something like this: No matter how much energy is added to increase the speed of a particle of mass, it approaches, but does not acheive the speed of light.**end edit in**edit in 6/19/02 Therefore you have a practical application of the paradox where the calculus 'sand box' cannot be used. If we place the limits you have described as paradox eradicating on the acceleration to speed of light formula which describes particle acceleration limits as a geometrical series, some can say, 'Weeellll, for all practical purposes the particle DOES achieve the speed of light. See!, this sort of infinite unreachability paradox formula has been solved and therefore a particle can acheive light speed. The paradox is solved.' Yet, this conclusion would be met with howls of dissapproval and 'crank' by those who would say that the energy input needed to accelerate the particle to light speed is infinite and therefore unacheivable.***end edit in***

The one in the plane. The patient is in the plane, so it is their hour which counts, not the hour of a ground observer. That's fairly obvious.

So, as a physicist, you have no interest in testing the validity beyond a single test? You would extrapolate absolute consistency of behavior of all time-tracking devices in all manner of FORs [varying speed plane rides, for example?]

You seem confused about this.

To claim confusion is a rhetorical side-step. How do the twins anticipate, plan for, and avoid collision? Does the at-rest twin trust the measurements observed of the other one? The 'where is the other one' question in relation to trajectories and possible collision intersect in the real world. If the only answer to this scenario is: 'you are confused' then why converse at all. The concern is valid. Your focus is on post-collision, my concern is the anticipation of a collision, and how a twin is to prepare for it, based on relativistic calculations/observations. If relativity cannot help predict the collision and allow different FORs to map out FOR intersections, then this is obviously not the theory to turn to for high speed interactions.

Perhaps you could give me an example of relative motion in which you think the appearance would differ from the reality? Be careful to explain how you tell the difference between the appearance and the reality.

This is inherent in the relativistic calculations. Where I measure my twin, by reception of the light signal, does not correspond with the actual concurrent location of the twin. The signal is not the object. Referencing back to anticipating a collision we have a critical interaction where discerning between appearance and reality is crucial. 'Oh look, a message from my twin, it says he will be here in 30 minutes and there is the visual image of him.' Where one twin sees the other and where the other twin actually is, do not correspond. In a stellar example, if we accept that the sun bends starlight, then there is an apparent image of location which does not correspond with the actual location. Then add to this the delay of light between source and sun and observer. ***Edit in 6/19/02 I see that the stellar example does not directly answer your relative motion question...it is involving a claimed relativistic effect and real vs. apparent images. The signal/appearance vs. actual location is more to your question. **end edit in***

By the way, here is a more current anticipated experiment to test GR **www.ecn.purdue.edu/AAE/News/longuski.pdf[/url]-**Space test**-[/URL] ** though it is a year old. I have not found out if this is still beig pursued.

Forget the schrodinger stuff...it was just an attempt to have a little fun.

hasta luego,
137

 

[137]

goofy tag

I kept trying to make the URL link clean, but it kept reverting to what you see in the previous post. I give up

 

[137]

"Paradoxes?!?,... we don't need no stinkin' paradoxes!"

The paradoxes of Zeno

A link for the enjoyment of all.

 

[137]

Assynchronous deaths

James R,

Time constraints will lead to short posts. It should be a nice relief to some.

OK, lets scrap the old folks death testing analysis and focus on a tried and true test subject, which has been used and bred for many decades now. Fruit flies. With a [roughly] 24 hour life cycle, combined with the ease of cloning, we have not only twins but milluplets[made up word], if we want. We can do many tests on millions of expendable, short lived subjects. We correct for as many environmental variables as possible to duplicate the living conditions of the little beasties and fly half the fruit fly clones around the world UNTIL all are dead and note the exact time of death for as many as possible. The same is done on the earth bound sibling fruit flies. This test can be done on as many groups as necessary at extremely low cost. If speed effects truly slow biological clocks, then statistically, we should show a heavy leaning towards long lived fast-plane borne fruit flies.

The test can be done at varying altitudes to see if there is a variation depending upon the strength of gravity.

*School me on whether SR and the speed of a plane predicts that the occupants should experience any clock slowing/rod shortening variations depending upon whether the plane is:
a] 10,000 feet vs. 20,000 feet vs. 30000 feet
&
b] the plane is flying with the earth's rotation; against rotation or perpindicular to the rotation

I am all for pushing for this sort of low cost experiment. It falls under the domain of 'what affects on biology occur in high speed', anyway. In these low budget times, you would think the space-happy countries would love to do this sort of thing.

until we meet again....I am getting too busy for frequent posting...[[sound of cheers is heard from post readers]]
137

 

[allant]

Tom

Been down this route. I have an experiment that tells the difference between your theory and SR. Consider that an electron is flying round in a circle. Now if the slowdown is less push by the reduced difference in velocity of the pushee and the pushor. then the mass is the same right ?. But SR says the mass is increased.

Ok now if we push at right angles to the direction the electron is flying, we have no difference in velocity IN THE DIRECTION WE ARE PUSHING. So if we push we should see the same mass and the same effort required, regardless of the speed ?

Well in a cyclotron the magnetic field that is needed to push sideways to keep the electron moving in a circle needs to be increased to allow for the increased mass. As the speed increases the force needed increases to counter the centrifugal force, but close to C it needs to increase even more exactly as SR predicts.

QED ? You might argue, to keep your theory intact, you need to assume that the same rule applies when the field/force is at right angles to the direction of travel, but this rapidly gets complicated, ridiculous and the math the same except for semantics as for increased mass.

 

[allant]

Does a photon have mass ?

First we need to define what we mean by mass. There are four definitions in use !

First inertial mass. If we exert a force on an object, we can see/measure an effect of it speeding up. If we compare two objects and exert the same force and we observe different rates of acceleration. If we use a diffrent strength of force we see diffrent acceleartions. We then discover the relation F/A = ? We can decide to call this quantity its inertial mass. By yet more experiments we can find that this is ALWAYS equal to momentum devide by velocity, so for particles that travel at C we can talk of it having momentum. Does a photon have inertia mass. The answer is yes, and we can talk of a photon having momentum. The value of the mass is proportional to the lights frequency, so not all photons have the same inertial mass or the same momentum.

2) Gravitational mass. As above but using the space time curve also known as the force of gravity. As above we get the same answer yes, photons have a gravitational mass. Exactly the same as the inertial mass. If gravitational mass always equals inertial mass, which experiments have shown true so far, is one of the unanswered questions.

3) Relatavistic mass. Now this should really be two relativistic inertail mass and relativistic gravitational mass. But in this theoretical world, gravitational mass does not exists except as the cause of space time curvature. This is measured the same as above, but allows for the differences when the mass we are measuring is moving close to the speed of C relative to the ? doing the measuring. Now photons do have this mass the same value as above.

4) Rest Mass. Again we can split in two. But this is defined as the mass we see/measure or should see when the relative speed is zero. Now since we cant measure a photon when not moving relative to us, we have to calculate it. What we do is calculate how massive a particle it has to be at rest to give the measured mass at C. The answer turns out to be 0. So a photon has zero rest mass.

This is all sumed up in maths as

Mrelativistic = Mrest + E/C^2

Which means the mass we measure depends on the rest mass plus the energy of the object as mass. Now a photon is odd in that it has energy and a velocity but no rest mass. Matter is odd in that it has a rest mass, (kinetic) energy and a variable velocity.

CleAr aS mUD ?

 

[James R]

137,

I think your fruit fly experiment is impractical due to the extremely small time dilation effects which will be involved.

Re-iterating my reasoning on this:
1. Relativity predicts time dilation for all "clocks", no matter what their physical form.
2. Some particular examples have been tested experimentally and found to agree with the relativistic predictions.
3. Therefore, applying the generality of the derivation of the relativistic predictions, it is safe to assume that other types of clocks will also undergo time dilation in the same way as the ones which have actually been tested.

That's good enough for me. To take an analogy:

1. Newtonian gravity theory predicts that all objects dropped from a height will fall to the ground.
2. This has been tested with balls, rocks, people, etc. etc.
3. Given the generality of the arguments which lead to the theoretical result, it is safe to assume that other (untested) objects will also fall when dropped.

For example, I can safely assume that if I dropped the Empire State Building from a height (something which has never been done) it would fall to the ground.

The point is: I don't need to test every conceivable object to be confident that a scientific theory is generally applicable.

 

[137]

drop fly

James R,

Then the fruit fly experiment needs to wait until we can get them going at a sufficient speed, no?
Response to your reasoning:
#1. The original SR predictions may have been elaborated upon to include all periodic events that are used to 'clock' time, but this is a sweeping inclusion to bolster the prediction. A large majority of the objects which fall under the prediction are precluded from testing, due to technological limits, i.e. fruit fly aging comparison.
#2. Very few SR tests have been done, relative to the breadth of application. Most references are still heavily weighted towards narrowly devized and tested predicitions, with no control group.
For example: Atomic clocks put in planes, flown around, and, 'oh look, there is a slow down relative to the earth one.' Case closed, lets start applying this to cosmological calculations. I am still building a catalog of proofs, which may very well make me eat my words, but I do not accept opinions that 'many experiments' and 'all the proof needed is there' without the data. What true scientist would?
It is interesting that Louis Essen who perfected the standard atomic clock found issue with SR as applied to time dilation.
GPS readings seem to point more and more to contradicting relativistic claims...when I am satisfied with the validity and sufficient number of pro and con links I will post them.
#3. If we freeze a metal and it contracts, then we measure a brick after cooling and it contracts, we conclude all things contract when cooled or frozen. No need to test further. Then water rears its ugly head and demolishes our theory. Are all relativists afraid of easily performed tests? As listed before, I propose that all manner of clocks be flown as fast as possible in all different directions. It is valid to test the validity of SR and affordable. There should be a synchronicity between all manner of timekeepers within the framework of a fast plane.
Still curious about the following:
*School me on whether SR and the speed of a plane predicts that the occupants should experience any clock slowing/rod shortening variations depending upon whether the plane is:
a] 10,000 feet vs. 20,000 feet vs. 30000 feet
&
b] the plane is flying with the earth's rotation; against rotation or perpindicular to the rotation
and:
The 'where is the other one' question in relation to trajectories and possible collision intersect in the real world. If the only answer to this scenario is: 'you are confused' then why converse at all. The concern is valid. Your focus is on post-collision, my concern is the anticipation of a collision, and how a twin is to prepare for it, based on relativistic calculations/observations. If relativity cannot help predict the collision and allow different FORs to map out FOR intersections, then this is obviously not the theory to turn to for high speed interactions.

response to your analogy:
#1 With a formula which anticipates a vacuum
#2 People worked on perfecting a vacuum and continued to test the theory. They did not rest on the laurels of other people's proclamations and formulas.
#3
feather and hammer on the moon The testing/proof-building is an ongoing need of science. If we followed your scientific mode of inquiry, testing becomes a seldom performed act. 'Hey, leave the feather and hammer at home...its already proven.'

The point is: I don't need to test every conceivable object to be confident that a scientific theory is generally applicable.

If you dwell only in the general, perhaps, but there are plenty of critical interactions and events, i.e. high speed interactions, which are touted as being within the realm of SR's application, yet, it appears from your understanding of it, SR cannot make any predictive interaction calculations or it defeats itself.
By the way, let me rephrase a particular question regarding time dilation. If each FOR cannot calculate its own time dilation, and the only way that a time dilation is proven is by one FOR's calculation of time dilation via the light signals of a 'twin' moving at some percentage of c, close to c, how can the appearance of time dilation of the viewing FOR prove actual time dilation within the other FOR. Feel free to wax poetic about my simple mindedness and ignorance and that it will take decades for me to understand, but ultimately, try to answer this as clearly as possible.

Cheers,
137

 

[Prosoothus]

137,

If we freeze a metal and it contracts, then we measure a brick after cooling and it contracts, we conclude all things contract when cooled or frozen. No need to test further. Then water rears its ugly head and demolishes our theory.

That was a good one!

Tom

 

[James R]

137,

<i>Then the fruit fly experiment needs to wait until we can get them going at a sufficient speed, no?</i>

It would become practical if very high speeds could be achieved for the flies, yes. But it is still unnecessary.

<i>#1. The original SR predictions may have been elaborated upon to include all periodic events that are used to 'clock' time, but this is a sweeping inclusion to bolster the prediction.</i>

How many times do I need to say it? SR is derived under the most general assumptions about space and time. It is not tied to any particular object or system of interest. Hence it is generally applicable to all objects moving in spacetime.

<i>Very few SR tests have been done, relative to the breadth of application.</i>

I can get you a list of about 20 experiments in a couple of seconds of searching on the web. That's just for a start. Surely you've found at least that number in your extensive searching so far?

<i>It is interesting that Louis Essen who perfected the standard atomic clock found issue with SR as applied to time dilation.</i>

Argument from authority is worth very little in science.

<i>If we freeze a metal and it contracts, then we measure a brick after cooling and it contracts, we conclude all things contract when cooled or frozen. No need to test further.</i>

Wrong. There is no all-encompassing theory of the thermal behaviour of solids which predicts that all solids contract on cooling. Therefore we need to look at each substance individually, or at groups of similar substances. The analogy does not hold for relativity.

<i>*School me on whether SR and the speed of a plane predicts that the occupants should experience any clock slowing/rod shortening variations depending upon whether the plane is:
a] 10,000 feet vs. 20,000 feet vs. 30000 feet
&
b] the plane is flying with the earth's rotation; against rotation or perpindicular to the rotation</i>

The time dilation and length contraction measured will depend on both the height and the speed, since there are two effects at work - gravitational time dilation and time dilation from relative motion. Both effects need to be taken into account. This turns out to be a reasonably complex calculation.

<i>The 'where is the other one' question in relation to trajectories and possible collision intersect in the real world. If the only answer to this scenario is: 'you are confused' then why converse at all. The concern is valid.</i>

Each observer can predict the time and place of the collision from his or her own observations, and they will both be correct in their own reference frame. Both observers <b>must</b> see the same events occur.

<i>If relativity cannot help predict the collision and allow different FORs to map out FOR intersections, then this is obviously not the theory to turn to for high speed interactions.</i>

It can.

<i>If each FOR cannot calculate its own time dilation, and the only way that a time dilation is proven is by one FOR's calculation of time dilation via the light signals of a 'twin' moving at some percentage of c, close to c, how can the appearance of time dilation of the viewing FOR prove actual time dilation within the other FOR.</i>

You do know that no observer experiences time dilation in his own reference frame, don't you?

<i>Feel free to wax poetic about my simple mindedness and ignorance and that it will take decades for me to understand, but ultimately, try to answer this as clearly as possible.</i>

If my perception is that you don't understand, I will say so. I won't be bullied. That's the nature of frank scientific discussion. I won't pander to your ego, and hopefully you won't pander to mine. Ok?

 

[Crisp]

Hi Tom,

If we freeze a metal and it contracts, then we measure a brick after cooling and it contracts, we conclude all things contract when cooled or frozen. No need to test further. Then water rears its ugly head and demolishes our theory.

That was a good one!

True .

Bye!

Crisp

 

[137]

And then

But it is still unnecessary.

Furthering experimental evidence is always necessary. Validating claims is always necessary

How many times do I need to say it? SR is derived under the most general assumptions about space and time. It is
not tied to any particular object or system of interest. Hence it is generally applicable to all objects moving in spacetime.

Unsatisfactory defense. There are specific defenses of the specific application of SR. This thread is thick with them. Specific predictions [the presented formulas and thought experiments] upon specific objects [clocks and rods]. Are you denying that SR specifically deals with the family of clocks, measuring rods and mutually interacting FORs? Einstein made calculated decisions based on his reading of historical developments. His insight is not by fiat. His transformations are derived from transformation assumed to be real based on the inability to conceive that there was no ether. Maybe I am mis-reading you, but there is nothing off-mark in the line of inquiry which we have been pursuing.

I can get you a list of about 20 experiments in a couple of seconds of searching on the web. That's just for a start.
Surely you've found at least that number in your extensive searching so far?

What I find are references to the 'proofs' that propelled Einstein to stardom. Eddington and the flying atomic clocks...then we leap to distant phenomenon analysis under the strong assumption that Relativity is not to be questioned. It is to be used and that is that. What I am finding in my emails with NASA solar scientists is that the corona is a very active arena with high potential for interation with light. There has been no independent verification of the Eddington solar eclipse proofs with careful use of modern tools and using modern understanding of the sun's atmosphere to track all affecting variables. Same with the clock issue. As stated, emails with GPS folks point to the same issue. Relativistic effects predicted do not gel with reality. There are some experiments involving X-rays and the sun, but then again, the solar scientists say that the sun's corona wreaks havoc on EM waves. So go figure. Send me your search for the 20 you found.

There is no all-encompassing theory of the thermal behaviour of solids which predicts that all solids contract
on cooling. Therefore we need to look at each substance individually, or at groups of similar substances. The analogy does not hold for relativity.

Aahhh, so we need a unified thermal behavior of solids theory which can fit contractions and expansions under its umbrella. Now you argue from specific experimental evidence that precludes an all-encompassing theory. Now lets hide water from you and I prove by formula that the closer and closer atoms are brought to each other the smaller the interaction and hence the contraction of materials. I imagine a mathematical formula could be derived which appears to show that ALL physical systems contract when they cool. How would someone prove that there is an exception based on the formula? If we took the SR formula and re-worked it to apply to the slowing down of molecules and atoms as they cool[lets call it the Special Theory of Cool or SC], you know what we would get? Yep, that's right a contraction of rods. There would be NO room in the equation to anticipate an exception, yet water still exists and contradicts the absolutism of SC.

gravitational time dilation and time dilation from relative motion. Both effects need to be taken into account. This turns out to be a reasonably complex calculation.

Wait a minute, so you are saying that GR and SR need to be used in the calculation? I thought you said in concurrence with Einstein, that SR could handle the equation on its own? And if we deploy 39 satellites at every which level and direction, how does each satellite constantly correct for the other 38 satellites? Answer that I am getting from GPSers so far is, initial offset of a specific amount and that is it. Keep in mind, I am just as skeptical about these claims until I get all the details. My understanding is that SR would demand more than just an initial offsetof the clocks in order to set up the system for constant synchronizing ability.

Each observer can predict the time and place of the collision from his or her own observations, and they will both be correct in their own reference frame. Both observers must see the same events occur.

Will both observers accurately predict the collision from their own FOR which accurately allows for avoidance or decision? I will sit down and play with the calculations soon to see for myself.

137:If each FOR cannot calculate its own time dilation, and the only way that a time dilation is proven is by one FOR's
calculation of time dilation via the light signals of a 'twin' moving at some percentage of c, close to c, how can the
appearance of time dilation of the viewing FOR prove actual time dilation within the other FOR.

JAMES R:You do know that no observer experiences time dilation in his own reference frame, don't you?

Yes, I know this is the claim and this is why there is the question. Let me ask again "how can the appearance of time dilation of the viewing FOR prove actual time dilation within the other FOR." ? It just does is what many Relativists claim.

I won't pander to your ego, and hopefully you won't pander to mine. Ok?

I am not here for ego, I am here to question and respond related to this topic. You can either defend your position or not, and even if you said, 'I do not know that' then that does not disprove Relativity. If you know this subject in depth, then the challenge of defending its 'rightness' should do nothing but intensify your understanding of the theory, questions and objections to it from the lame to the intelligent. What I am attempting to do is wade through evasion of the question, whether intentional or not, and test the ability for someone to respond to my genuine inquiry. You are pretty much the only one left who is brave enough and, I assume, confident enough that you know your field and respond.

137

 

[allant]

QUOTE]Yes, I know this is the claim and this is why there is the question. Let me ask again "how can the appearance of time dilation of the viewing FOR prove actual time dilation within the other FOR." ? It just does is what many Relativists claim.[/QUOTE]

Maybe you wont buy as a proof but... Some Radioactive atoms have half lifes that are very short, on the order of millionths of a second. Now in coliders sometimes these exit at very close to the speed of light, these are consistantly measured as having far greater lifes, sometimes with huge differences say lasting tenths of a second.

Now as clocks go Radioactic half lives are bad cause it is random. But if you do it often enough you are either very lucky that only the fast moving ones lasted longer on average, or they are experiencing time dilation.

How do we know what they were ? Because of the products that create when they decompose. How do we now the half life ? Some collisions produce the same sustance at slow sppeds. How do we know how fast they are traveling ? Two ways some are charged and we can work it out from the cureve in the magnetic field. And we can work out from the energy sums stating with the tracks they leave in the bubble chamber or similar.

Just one of many things routinely noticed that show the SR/GR effects.

 

[James R]

137,

<i>Furthering experimental evidence is always necessary. Validating claims is always necessary.</i>

Yes. In this instance, the claims have been validated (within the limits of experimental error in individual experiments). All point to the conclusion that relativity is generally applicable.

<i>Are you denying that SR specifically deals with the family of clocks, measuring rods and mutually interacting FORs?</i>

Yes. In this context, "clock" is a term used to refer to any method for measuring time. "Rod" is a term used to refer to any object.

<i>What I am finding in my emails ...</i>

Perhaps you could reproduce those emails here, or preferably get some reliable references and post those. At this stage, you're asking me to go on hearsay.

<i>Send me your search for the 20 you found.</i>

Here's just one link, to get you started:

<a href="http://math.ucr.edu/home/baez/physics/Relativity/SR/experiments.html" target="_blank">What is the experimental basis of special relativity?</a>

<i>Now lets hide water from you and I prove by formula ...</i>

You can't prove by formula. I'm not claiming that relativity is proved by its own framework. Of course it isn't. I am claiming that there is strong evidence from a number of different experiments that relativity theory is generally applicable and correct. The question is: can you find any evidence which disputes this?

<i>Wait a minute, so you are saying that GR and SR need to be used in the calculation? I thought you said in concurrence with Einstein, that SR could handle the equation on its own?</i>

In the airplane example, both SR and GR are needed since there is a gravity field involved and SR does not deal with gravity. (Actually, more exactly, you could say that only GR is needed, since it encompasses SR as a special case.)

And no, I didn't claim that SR could handle this particular thing on its own.

<i>And if we deploy 39 satellites at every which level and direction, how does each satellite constantly correct for the other 38 satellites? Answer that I am getting from GPSers so far is, initial offset of a specific amount and that is it.</i>

Perhaps it has something to do with the fact that all the satellites orbit at the same constant height, and they are all at a constant distance from each other. (Just an educated guess, until I get more information.)

<i>Will both observers accurately predict the collision from their own FOR which accurately allows for avoidance or decision?</i>

Absolutely.

<i>Let me ask again "how can the appearance of time dilation of the viewing FOR prove actual time dilation within the other FOR." ?</i>

There is no distinction between "appearance" and "actual" in this case. What an observer sees <b>is</b> his reality.

 

[137]

contracted response

allant...valid arena of experiments and effects which I will move towards in inquiry, but my focus is on the root of SR. The experiments and evidence fall within the accepted range of predicition of SR is my surface understanding. The foundation must be solid...
James R:

the claims have been validated (within the limits of experimental error in individual experiments). All point to the conclusion that relativity is generally applicable.

Still on my plate is my personal attempt to catalogue the data in full. Not just conclusions. The roots of the acceptance of Relativity are awash in sloppy science. This is becoming more and more apparent. Look up what is available regarding Eddington's proofs. By any standard, the selective inclusion of data is a poor foundation to build upon. A catalog of all experimental evidence in key experiments is my desire....

Perhaps you could reproduce those emails here

Exactly...when I can guarantee that the emails are from respected scientists, not PR people, I will post them and websites. If you look, my focus in this forum is to not speak in hearsay but post original sources of the theory and the critics. If I made a living researching this would be faster.

Here's just one link, to get you started:

Up through section three all of the experiments involve isotropy of speed of light...basically proof that there is no ether. Of course this is consistent with SR in the sense that no ether is needed. Part 4 begins the heart of what we speak of...I will read it at work and report back.

The question is: can you find any evidence which disputes this?

The appearances vs. reality issue which at least for now we have come to an impasse [sp?] There are other claims...but I am studying them.

And no, I didn't claim that SR could handle this particular thing on its own.

I apologize for attributing this to you, BUT Einstein claimed throughout his life that SR could handle the constant accel vs rest frame alone.

There is no distinction between "appearance" and "actual" in this case. What an observer sees is his reality.

This is key. So the time dilation is a reality for the other twin only in the observing twin's FOR? How does one leap from Observation to application to the other? If I see you on a train 3 miles away you appear to be 1 inch tall...My observation is my reality. Does this make it true in essence?

 

[James R]

137,

<i>I apologize for attributing this to you, BUT Einstein claimed throughout his life that SR could handle the constant accel vs rest frame alone.</i>

It can do that. It can't deal with gravity.

<i>So the time dilation is a reality for the other twin only in the observing twin's FOR?</i>

Your question doesn't make sense as written. The time dilation observed by one twin is true for that twin. Time dilation observed by the other twin is true for that twin.

<i>How does one leap from Observation to application to the other?</i>

If you want to calculate differences between frames of reference, you use the Lorentz transformations. They are the basic tools of relativity.

<i>If I see you on a train 3 miles away you appear to be 1 inch tall...My observation is my reality. Does this make it true in essence?</i>

That's a philosophical question rather than a scientific one. The science says you have no way to distinguish between your observation and reality.

 

[137]

more buts

Your question doesn't make sense as written. The time dilation observed by one twin is true for that twin. Time dilation observed by the other twin is true for that twin.

It was intentionally written that way, as it is my reading of the cross-referencing proof of time dilation. Based on your statement, time dilation is solely a matter of observation.

If you want to calculate differences between frames of reference, you use the Lorentz transformations. They are the basic tools of relativity.

This is one of the conundrums of SR. It uses a formula which was developed to uphold the existence of the ether.

That's a philosophical question rather than a scientific one. The science says you have no way to distinguish between your observation and reality.

Perhaps the term essence is to philosophical. This word can be replaced with reality. Are you saying that even in non-SR FOR variation based solely on distance, that my observation that my twin 3 miles away is 1" tall is true. If you are actually standing by this interpretation, then the dialogue must end. This smacks of Deconstructionism which has no place in any science. Are you throwing out all sensibility? Does the conglomeration of atomic components of the human body which measured against a standard measure contract and become 1" tall in the onbserver's reality? Please tell me you are not that far gone into the delusional. The thousand years of science which has led to our era is repleat with measurements to the nano scale. The statistical size of atoms has been mapped. The invariance parameters of their interations and 'compressibility' are continually being mapped, and yet you say the science says you cannot distinguish between observation and reality? Correct me if I have misinterpreted your response.
To expand. Do you understand that as a base FOR for the development of science, the Earth standards of measure have become more and more refined with a focus on precision, and that these precise standards are applied to further science and the consistency of physics? Physics is the opposite of fuzzying out the observer/reality pairing. If anything physics is saying, 'Do not always believe what you see, for appearances can be deceiving.' I hope I have mis-understood you...
If the 'science' is saying you cannot distinguish between observation and reality, then the science is incomplete.
137